Conventionally, apparatuses are known for continuously delivering a sheet from an original material roll formed by winding the sheet.
When a remaining sheet amount of the original material roll becomes small in an apparatus of this type, for example, a joining operation of sheets such as that shown in FIG. 29 to FIG. 32 is performed.
Specifically, in order to perform the joining operation, as shown in FIG. 29, an original material roll (hereinafter, referred to as a standby-side original material roll) R2 which stands by for delivery of a sheet W is installed in advance adjacently to an original material roll (hereinafter, referred to as a delivery-side original material roll) R1 which delivers the sheet W.
As shown in FIG. 30, when a remaining amount of the sheet W of the delivery-side original material roll becomes small, an end section of the sheet W is retrieved from the standby-side original material roll R2 and an adhesive (for example, a tape T) is affixed to the end section of the sheet W.
Next, as shown in FIG. 31, using the tape T, the end section of the sheet W of the standby-side original material roll R2 is connected to an intermediate section of the sheet W of the delivery-side original material roll R1 and the sheet W of the delivery-side original material roll R1 is cut at an upstream position (a position denoted by a triangle in FIG. 31) relative to the tape T.
Accordingly, as shown in FIG. 32, tension applied to the sheet W on a downstream side of both original material rolls R1 and R2 is applied via the tape T to the sheet W of the standby-side original material roll R2, and the sheet W is delivered from the standby-side original material roll R2. In other words, the standby-side original material roll R2 performs a role of a next delivery-side original material roll R1.
As an apparatus for automatically performing the joining operation described above, for example, an apparatus described in Patent Literature 1 is known.
The apparatus described in Patent Literature 1 includes: a roll holding unit which holds a delivery-side original material roll and a standby-side original material roll; a joining unit which joins a sheet of the standby-side original material roll to a sheet of the delivery-side original material roll; and an XY mobile robot which retrieves an end section of the sheet of the standby-side original material roll and which guides the end section to a suction holding unit.
The joining unit includes a suction holding member configured to hold the end section of the sheet of the standby-side original material roll by suctioning the end section.
An adhesive tape is attached to the end section of the sheet held on the suction holding member, and the end section of the sheet is joined to an intermediate section of the sheet of the delivery-side original material roll by an adhesive force of the adhesive tape.
Patent Literature 1 does not clarify how the end section of the sheet held by the suction holding member is joined to the sheet of the delivery-side original material roll.
For example, the end section of the sheet held by the suction holding member is conceivably joined to the sheet of the delivery-side original material roll by moving the suction holding member toward the sheet of the delivery-side original material roll.
When the suction holding member moves in a direction approaching the standby-side original material roll during a movement of the suction holding member toward the sheet of the delivery-side original material roll, slack is created on a sheet between the suction holding member and the standby-side original material roll and a delivery speed of the sheet after a joining operation may change.
Therefore, the suction holding unit must be moved with respect to the delivery-side original material sheet so that slack is not created on the sheet between the suction holding member and the standby-side original material roll.
However, in this case, there is a risk that tension created on the sheet between the suction holding member and the standby-side original material roll changes a holding position of a tip section of the sheet with respect to the suction holding member, and the end section of the sheet can no longer be accurately joined to a sheet of the delivery-side original material roll.